Method for improving the workability of a binder composition comprising Portland cement, calcined clay and limestone

Abstract

The present invention relates to a method for improving the workability of a binder composition comprising calcined clay, limestone, and Portland cement. The method comprises the step of adding an admixture comprising at least one PCE and at least one additive selected from sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids. The invention also relates to an admixture used in the method and to a curable composition, in particular concrete and mortar, obtainable by the method.

Description

Technical Field

[0001] The present invention relates to a method for improving the workability of a binder composition comprising calcined clay, limestone, and Portland cement. The method comprises the step of adding an admixture comprising at least one PCE and at least one additive. The invention also relates to the admixture used in the method and to curable compositions, in particular concrete and mortar, obtainable by the method. Background Art

[0002] Cement-based building materials, especially concrete and mortar, rely on cement-based materials as binders. Cement-based binders are typically hydraulic binders, the most abundant of which is Portland cement. Due to the rapid pace of infrastructure development in much of the world, there is a huge demand for Portland cement. However, the use of Portland cement is associated with a high environmental footprint. A major reason for this is the high CO₂ emissions associated with its production, estimated at 0.8 kg CO₂ per kg of Portland cement clinker produced. Consequently, various approaches have been taken to at least partially replace Portland cement in binder compositions in concrete and mortar.

[0003] One particularly attractive approach is to partially replace Portland cement clinker with supplementary cementitious materials such as fly ash or slag. However, the use of many supplementary cementitious materials is limited by their availability or by technical constraints in the prior art.

[0004] Portland-limestone cement is a type of Portland cement specified by standard EN 197-1:2000. These cements may contain up to 20% by weight or even up to 35% by weight of limestone in addition to Portland clinker. However, replacing Portland clinker with limestone of similar or higher surface area in ground cement generally results in lower strength because most of the limestone is unreactive. Therefore, several composite binders have been developed to overcome this problem.

[0005] WO 2010 / 130511 discloses a binder composition comprising Portland cement clinker, calcined clay or metakaolin and limestone. This binder composition exhibits yield compressive strength comparable to that of pure Portland cement-based materials, but with lower CO2 emissions, particularly if higher amounts of metakaolin are present.

[0006] WO 2014 / 032018 discloses concrete with a low cement content, in which Portland cement clinker is replaced by admixtures of limestone and metakaolin. It is shown that fine limestone powder is necessary to achieve a compressive strength development similar to that of pure Portland cement-based materials.

[0007] Admixtures can be used to further improve the strength of certain binder compositions based on Portland clinker, calcined clay and limestone. The use of trialkanolamines is described, for example, in US 2019 / 0144334.

[0008] However, when using binder compositions comprising Portland cement clinker, metakaolin, and limestone, problems related to workability are often encountered. In particular, when higher amounts of calcined clay or metakaolin and / or fine limestone material are used in such binder compositions, lower workability is encountered, which can be measured, for example, as a lower initial slump flow or a reduced slump life. Or, in other words, the water requirement of such binder compositions is increased to achieve the same workability.

[0009] Water reducers, plasticizers, and superplasticizers are commonly used admixtures in concrete and mortar production. These materials can be used to reduce the water requirement of a given concrete or mortar mixture and / or improve its workability. Polycarboxylate or ether (PCE) is a particularly suitable superplasticizer for cement-based building materials. Such polycarboxylate ethers are described, for example, in WO 2010 / 085425 and EP 1138697.

[0010] However, when PCE is used with a binder composition comprising Portland cement clinker, metakaolin, and limestone, workability remains unsatisfactory, and in particular, the slump life, i.e., the retention of a certain slump flow over time, is insufficiently long. Consequently, the PCE dosage must be increased to achieve the desired workability, significantly increasing the cost of the overall material composition. Furthermore, the use of PCE in such binder compositions, especially at increased dosages, often results in system lags, and consequently, the compressive strength after a given time may be too low.

[0011] CN 110627393 discloses a mortar mixture comprising Portland cement clinker, calcined clay and limestone as a binder composition and a polycarboxylate / ether-based water reducer. However, the effect on workability and in particular slump life is not reported.

[0012] Therefore, there is a need for suitable methods and admixtures for binder compositions comprising Portland cement clinker, metakaolin, and limestone that overcome the shortcomings of the prior art. SUMMARY OF THE INVENTION

[0014] The object of the present invention is to provide a binder composition comprising calcined clay, limestone and portland cement and having improved workability. Preferably, this binder composition should not show strong hardening delay. In particular, after curing for 1 day, the workability of increase should be achieved without significantly affecting strength. Another object of the present invention is to provide a curable composition, especially concrete and mortar using this improved binder composition, wherein the binder composition comprises calcined clay, limestone and portland cement.

[0015] It has been found that the workability of a binder composition comprising calcined clay, limestone and Portland cement can be significantly improved by adding an admixture comprising at least one polycarboxylate ether or polycarboxylate (PCE) and at least one additive. The present invention therefore relates to a method for improving the workability of a binder composition comprising calcined clay, limestone and Portland cement, the method comprising the step of adding an admixture comprising at least one PCE and at least one additive. The additive is selected from sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids. Surprisingly, it has been found that at least one additive selected from materials commonly used as retarders in concrete and mortar applications, when used in the method of the present invention, does not delay hardening to a level that is unacceptable for practical use. Detailed Description of the Invention

[0017] In a first aspect, the present invention relates to a method for improving the workability of a binder composition comprising calcined clay, limestone and Portland cement, said method comprising the step of adding an admixture comprising at least one PCE and at least one additive.

[0018] In the context of the present invention, the term slump life refers to the amount of time that the initial slump expansion of the binder composition is reduced to a given minimum value experienced. The slump life can be determined according to EN 12350-8 by measuring the slump expansion of the binder composition mixed with water. The measurement of the slump expansion is repeated on the material of the same mixture after the different times after mixing with water. In the context of the present invention, the slump life is the amount of time that the slump expansion measured according to DIN EN 12350-8 is reduced to 37.5mm (it is still measurable minimum value) experienced. If from adding water in the binder composition until the slump expansion of the binder composition drops to the time of given minimum level (being 37.5mm in the present case) experienced, than from adding water in the contrast binder composition until the slump expansion of the contrast composition drops to the time of given minimum level (being 37.5mm in the present case) experienced long, then the binder composition has the slump life of increase. The slump expansion according to EN 12350-8 is a measure of the workability of a binder composition. The slump life refers to the period of time during which the workability of a binder composition does not drop below an acceptable level. Thus, an increased initial slump expansion and / or an increased slump life are measures of increased workability.

[0019] The method of the present invention is a method for improving the workability of a binder composition comprising calcined clay, limestone and portland cement. The measure of workability is slump expansion and / or slump life. The particularly preferred measure for workability is slump life. In the context of the present invention, the initial slump expansion and / or the slump life of the increase correspond to the workability of the increase. Therefore, the method of the present invention increases the initial slump expansion of the binder composition and / or increases the time from adding water to the binder composition until the slump expansion of the binder composition drops to a given minimum level (37.5mm in this case). The increase in this initial slump expansion and / or slump life is relative to the same binder composition, but without the addition of the admixture of the present invention. Therefore, the improvement in workability is relative to the same binder composition, but without the addition of the admixture of the present invention. In addition, adding the admixture of the present invention to the binder composition of the present invention will not significantly delay the hardening of the binder composition after adding water.

[0020] Particularly preferably, the method of the present invention is a method of increasing the slump life of a binder composition comprising calcined clay, limestone and Portland cement.

[0021] The binder composition herein is a mineral binder composition. The mineral binder composition of the present invention comprises calcined clay, limestone and Portland cement.

[0022] Throughout the present invention, the term "clay" refers to a solid material consisting of at least 30% by weight, preferably at least 35% by weight, and in particular at least 75% by weight, in each case relative to its dry weight, of clay minerals. Such clay minerals preferably belong to the group of kaolins (e.g., kaolinite, dickite, nacrite, or halloysite), smectites (e.g., montmorillonite, nontronite, or saponite), vermiculites, serpentine, palygorskite, sepiolite, chlorite, talc, pyrophyllite, micas (e.g., biotite, muscovite, illite, glauconite, chrysocolla, and polysilicon muscovite), or mixtures thereof. Particular preference is given to clay minerals belonging to the group of kaolins, in particular kaolinite, and micas, in particular muscovite and illite, and mixtures thereof. Calcined clay (CC) is a clay material that has been heat-treated, preferably at temperatures between 500 and 900° C., or flash-calcined at temperatures between 800 and 1100° C. Suitable rapid calcination methods are described, for example, in WO 2014 / 085538. Calcined clay is an anhydrous material. According to an embodiment, the calcined clay is prepared separately from the other ingredients of the binder composition, in particular from the Portland cement and / or other pozzolans and / or latent hydraulic materials present, by heat treatment. In the context of the present invention, it is preferred that during the calcination of the clay, the clay material is dehydroxylated to an amorphous material while preventing the formation of crystalline high-temperature aluminosilicate phases such as mullite. Calcined clay, in particular calcined kaolinite, is generally amorphous, has a significantly higher specific surface area than the original clay, and has pozzolanic activity. According to a particularly preferred embodiment of the present invention, the calcined clay is metakaolin. Metakaolin is a material obtained by calcining kaolinite or a kaolinite-rich mineral, for example, with a kaolinite content of at least 30% by weight, preferably at least 35% by weight, relative to its dry weight. The calcination temperature for producing metakaolin is generally in the range of 500-900°C.

[0023] According to an embodiment, the calcined clay is ground into a powder having a residue at 45 μm measured according to ASTM C 430-96 (2003) of at least 0.5 wt%, preferably at least 2 wt%, still more preferably at least 10 wt%, especially at least 20 wt%.

[0024] In a preferred embodiment of the present invention, the chemical composition of limestone (L) and Portland cement (P) is as defined in standard EN 197-1:2011. Alternatively, limestone (L) may also represent magnesium carbonate, dolomite, and / or a mixture of magnesium carbonate, dolomite, and / or calcium carbonate. It is particularly preferred that limestone (L) within the scope of the present invention is a naturally occurring limestone consisting primarily of calcium carbonate (typically calcite and / or aragonite), but typically also containing some magnesium carbonate and / or dolomite. Limestone (L) may also be a naturally occurring marl.

[0025] In the context of the present invention, limestone (L) is a ground material that has not been heat-treated. In particular, the limestone has not been decarbonized. According to an embodiment, the limestone has a carbon content of 3'000-15'000 cm 2 / g of Blaine surface area.

[0026] The Blaine surface area is measured as described in standard EN 196-6:2010.

[0027] According to an embodiment, the portland cement is of type CEM I, CEM II, CEM III, CEM IV or CEM V according to standard EN 197-1. Portland cements described in other standards, such as ASTM standards or Chinese standards, are likewise applicable. According to a preferred embodiment, the portland cement is of type CEM I. According to an embodiment, the portland clinker content in the portland cement of the invention is at least 35% by weight, preferably at least 65% by weight, in particular at least 95% by weight, each based on the total dry weight of the cement. According to an embodiment, the portland cement clinker has an aluminum content, expressed as Al2O3, of less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, in each case relative to the total dry weight of the clinker. According to a particularly preferred embodiment, the Blaine surface area of the portland cement measured according to standard EN 196-6:2010 is 1500-10000 cm 2 / g, preferably 2 000-9000cm 2 / g, especially 3000-7000cm 2 Preferably, the sulfate content of the Portland cement of the present invention is optimized so that the SO3 content is not greater than 4.0% by weight, relative to the total dry weight of the cement.

[0028] According to an embodiment, the binder composition of the present invention comprises calcined clay (CC), limestone (L) and Portland cement (P) in the following weight ratios:

[0029] P:CC is 33:1 to 1:1, preferably 8:1 to 1:1,

[0030] CC:L is from 10:1 to 1:50, preferably from 10:1 to 1:33, more preferably from 5:1 to 1:10, and

[0031] P:L is from 20:1 to 1:4, preferably from 5:1 to 1:1.

[0032] According to an embodiment, the binder composition of the invention consists of in each case at least 65% by weight, preferably at least 80% by weight, more preferably at least 92% by weight, relative to the total dry weight of the composition.

[0033] According to an embodiment of the present invention, the binder composition comprises a mixture of the following substances:

[0034] a) 25 to 100 parts by mass of Portland cement (P),

[0035] b) 3-50 parts by mass of calcined clay (CC), especially metakaolin,

[0036] c) 5 to 100 parts by mass of limestone (L).

[0037] In particular, in this binder composition, the mass ratios of calcined clay (CC), limestone (L) and portland cement (P) are as follows:

[0038] P:CC is 33:1 to 1:1, preferably 8:1 to 1:1,

[0039] CC:L is from 10:1 to 1:50, preferably from 10:1 to 1:33, more preferably from 5:1 to 1:10, and

[0040] P:L is from 20:1 to 1:4, preferably from 5:1 to 1:1.

[0041] According to a specific embodiment of the present invention, the binder composition consists of a mixture of the following substances:

[0042] a) 50 parts by mass of Portland cement (P),

[0043] b) 20-50 parts by mass of calcined clay (CC), especially metakaolin,

[0044] c) 10 to 50 parts by mass of limestone (L).

[0045] In particular, the binder composition of the present invention comprises not more than 5 wt.-%, preferably not more than 2 wt.-%, relative to the total dry weight of the binder composition, of calcium aluminate cement and / or calcium sulfoaluminate cement according to EN 14647. In particular, the binder composition of the present invention has a higher content of Portland cement than of calcium aluminate cement and / or calcium sulfoaluminate cement.

[0046] According to an embodiment, the binder composition of the present invention further comprises calcium sulfate in an amount of 1-8 wt. % relative to the total dry weight of the composition. The binder composition of the present invention does not comprise calcium sulfate as the main binder. The calcium sulfate may be in the form of gypsum, calcium sulfate dihydrate, calcium sulfate hemihydrate (α or β form) and / or anhydrite.

[0047] According to an embodiment, the binder composition of the present invention further comprises a latent hydraulic and / or pozzolanic material. Suitable other latent hydraulic and / or pozzolanic materials are, for example, volcanic rock, pumice, glass dust, diatomaceous earth, pyrogenic silica, precipitated silica, slag, fly ash, silica fume and / or burned slate. According to certain embodiments, the binder composition comprises up to 20% by weight, preferably up to 5% by weight, of other latent hydraulic and / or pozzolanic materials, in each case relative to the total dry weight of the composition.

[0048] Thus, a suitable binder composition according to the invention may consist of at least 65% by weight, preferably at least 80% by weight, more preferably at least 92% by weight of calcined clay (CC), limestone (L) and Portland cement (P), and 1-8% by weight of calcium sulfate, the weight ratios of calcined clay (CC), limestone (L) and Portland cement (P) being in the range of P:CC from 33:1 to 1:1, preferably from 8:1 to 1:1, CC:L from 10:1 to 1:50, preferably from 10:1 to 1:33, more preferably from 5:1 to 1:10, and P:L from 20:1 to 1:4, preferably from 5:1 to 1:1, in each case relative to the total dry weight of the composition.

[0049] According to an embodiment of the present invention, the binder composition comprises 92-99 wt % of a mixture of the following components relative to the total dry weight of the binder composition, and 1-8 wt % of calcium sulfate relative to the total dry weight of the binder composition, wherein the components are:

[0050] a) 25 to 100 parts by mass of Portland cement (P),

[0051] b) 3-50 parts by mass of calcined clay (CC), especially metakaolin,

[0052] c) 5-100 parts by mass of limestone (L).

[0053] According to a specific embodiment of the present invention, the binder composition comprises 92-99 wt % of a mixture of the following components relative to the total dry weight of the binder composition and 1-8 wt % of calcium sulfate relative to the total dry weight of the binder composition, wherein the components are:

[0054] a) 50 parts by mass of Portland cement (P),

[0055] b) 20-50 parts by mass of calcined clay (CC), especially metakaolin,

[0056] c) 10-50 parts by mass of limestone (L).

[0057] In particular, in this binder composition, the mass ratios of calcined clay (CC), limestone (L) and portland cement (P) are as follows:

[0058] P:CC is 33:1 to 1:1, preferably 8:1 to 1:1,

[0059] CC:L is from 10:1 to 1:50, preferably from 10:1 to 1:33, more preferably from 5:1 to 1:10, and

[0060] P:L is from 20:1 to 1:4, preferably from 5:1 to 1:1.

[0061] According to a preferred embodiment, the binder composition comprises 92-99 wt. % of a mixture of the following components relative to the total dry weight of the binder composition and 1-8 wt. % of calcium sulfate relative to the total dry weight of the binder composition:

[0062] a) 25 to 100 parts by mass of Portland cement (P),

[0063] b) 3-50 parts by mass of calcined clay (CC), especially metakaolin,

[0064] c) 5-100 parts by mass of limestone (L).

[0065] This binder composition does not contain any other latent hydraulic and / or pozzolanic materials, in particular does not contain any one or more of volcanic rock, pumice, glass dust, diatomaceous earth, fumed silica, precipitated silica, slag, fly ash, silica fume and / or burned slate.

[0066] The binder composition of the present invention can be obtained by mixing the components in dry form with each other. Suitable mixing methods are known to those skilled in the art. In particular, the binder composition of the present invention can be obtained by mixing calcined clay, limestone and optionally calcium sulfate with each other and then blending the mixture with Portland cement. However, other mixing orders are also possible. It is also possible to grind two or more components of the binder composition together. However, it is preferred in this context that the calcined clay is ground separately from the other components. According to a particularly preferred embodiment, the binder composition of the present invention is obtained by mixing the components of the binder composition in dry form. In the context of the present invention, it is particularly not possible to prepare the binder composition by mixing the components and then performing a heat treatment or sintering process. Thus, for example, it is not possible to prepare the binder composition of the present invention by mixing calcined clay, limestone, optionally calcium sulfate and Portland cement and then heating the resulting mixture to a temperature above 150° C. (in particular in a furnace).

[0067] Preferably, the binder composition of the present invention is substantially free of water. Substantially free of water means that the water content is less than 5 wt %, preferably less than 1 wt %, and in particular less than 0.5 wt %, relative to the total weight of the binder composition. Therefore, the binder composition of the present invention is also often referred to as a dry binder composition.

[0068] The admixture used in the method of the present invention comprises at least one polycarboxylate ether and / or polycarboxylate (PCE). According to an embodiment, the at least one PCE is an admixture of a copolymer or two or more copolymers, wherein each copolymer comprises:

[0069] (i) a repeating unit A of the general structure (I),

[0070]

[0071] and

[0072] (ii) a repeating unit B of the general structure (II),

[0073]

[0074] in

[0075] Each R u are independently H or methyl,

[0076] Each R v independently of each other, H or COOM,

[0077] Each M is independently H, an alkali metal ion or an alkaline earth metal ion,

[0078] m=0, 1, 2 or 3,

[0079] p = 0 or 1,

[0080] Each R 1 Independently of each other -[YO]nR 4 , wherein Y is C2-C4 alkylene, and R 4 is H, C1-C20 alkyl, -cyclohexyl or -alkylaryl, and n=2-350,

[0081] And wherein the repeating units A and B in the copolymer have a molar ratio A:B of 10:90-90:10, preferably 20:80-80:20, more preferably 30:70-80:20, especially 35:65-75:25.

[0082] According to a preferred embodiment, YO is ethylene oxide and / or propylene oxide, especially ethylene oxide.According to a further preferred embodiment, n is 10-250, preferably 30-200, more preferably 35-200, especially 40-110.

[0083] The PCE according to the invention may be a statistical or non-statistical copolymer. Non-statistical copolymers are in particular alternating copolymers or block or gradient copolymers or mixtures thereof.

[0084] The copolymer CP of the present invention in the form of a random copolymer can be obtained by free radical polymerization of at least one ethylenically unsaturated carboxylic acid monomer of the general structure (Ia)

[0085]

[0086] and at least one ethylenically unsaturated monomer of the general structure (IIa),

[0087]

[0088] wherein Ru, Rv, M, m, p and R1 have the meanings given above, and the curled bond represents the cis and trans double bond isomers or mixtures thereof.

[0089] Suitable conditions for carrying out free-radical polymerization are known per se to the person skilled in the art and are described, for example, in EP1103570.

[0090] According to the present invention, the PCE of non-statistical copolymer, in particular block or gradient copolymer, can be preferably prepared by living radical polymerization. Living radical polymerization techniques include nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP) or reversible addition fragmentation chain transfer polymerization (RAFT). Living radical polymerization is carried out substantially in the absence of irreversible transfer or termination reactions. The number of active chain ends is low and remains substantially constant during the polymerization process. For example, in RAFT polymerization, this is achieved by using a RAFT agent and only a small amount of initiator. This allows the chain to grow substantially simultaneously and continuously throughout the polymerization process. This makes it possible to produce block or gradient copolymers using this method, and thus obtain a narrow molecular weight distribution or polydispersity of the polymer. This is impossible to achieve using conventional "free radical polymerization" or non-living radical polymerization.

[0091] The PCE according to the present invention can also be prepared by polymer-analogous conversion reactions. In particular, the PCE according to the present invention can be prepared by esterification of a homopolymer or copolymer comprising repeating units of the general structure (I) with a polyalkylene glycol of the general structure (III).

[0092] HO-R 1 (III),

[0093] wherein R1 has the meaning given above.

[0094] Suitable processes for producing PCE by esterification are known per se to the person skilled in the art and are described, for example, in EP1138697.

[0095] In addition to at least one ethylenically unsaturated carboxylic acid monomer of general structure (Ia) and at least one ethylenically unsaturated macromonomer of general formula (IIa), the PCE of the present invention may further comprise one or more other monomers M. These other monomers M may be selected from styrene, ethylene, propylene, butylene, butadiene, isoprene, vinyl acetate, vinyl chloride, acrylonitrile, N-vinyl pyrrolidone, hydroxyalkyl (meth)acrylates, (meth)acrylamide and / or maleimide.

[0096] Preferably, the molar proportion of one or more further monomers M is equal to or less than 66 mol%, preferably equal to or less than 50 mol%, more preferably equal to or less than 25 mol%, particularly preferably equal to or less than 10 mol%, and in particular equal to or less than 5 mol%, in each case based on all monomers forming the PCE copolymer. In a very preferred embodiment, the PCE is essentially free of further monomer units M. Thus, the PCE of the invention consists of at least 34 mol%, preferably at least 50 mol%, more preferably at least 75 mol%, more preferably at least 90 mol%, particularly preferably at least 90 mol%, and in particular 100 mol%, of repeating units A and B.

[0097] According to a particularly preferred embodiment, the admixture used in the process of the present invention comprises a polycarboxylate ether (PCE). According to an embodiment, the PCE is a copolymer comprising or consisting of:

[0098] (i) a repeating unit A of the general structure (I),

[0099]

[0100] and

[0101] (ii) a repeating unit B of the general structure (II),

[0102]

[0103] in

[0104] Each Ru independently represents hydrogen or methyl,

[0105] Each Rv independently represents hydrogen or COOM,

[0106] Each M is independently H, an alkali metal ion or an alkaline earth metal ion,

[0107] m = 0, 1, 2, or 3

[0108] p = 0 or 1,

[0109] Each R1 is independently -[YO]nR 4 , wherein Y is C2 to C4 alkylene, R 4 is H, C1 to C20 alkyl, cyclohexyl or alkylaryl, and n=2-350, and

[0110] The molar ratio of repeating units A and B in the copolymer CP is 10:90-90:10.

[0111] According to an embodiment, the at least one PCE may be in the form of a liquid solution or dispersion, preferably in water. The amount of PCE in such an aqueous solution or dispersion is preferably at least 20 wt. %, preferably at least 35 wt. %, relative to the total weight of the aqueous solution or dispersion.

[0112] According to other embodiments, the at least one PCE may be in solid form, in particular in powder form. Methods for producing PCE in powder form are known to those skilled in the art. A particularly suitable method is spray drying.

[0113] The admixture used in the process of the present invention comprises at least one additive. Additives in the context of the present invention are compounds selected from sugar acids, sugars, sugar alcohols, hydroxycarboxylic acids.

[0114] Sugar acid herein belongs to any one or more of aldonic acid, ulosonic acid, uronic acid or aldonic acid. Preferably, it is aldonic acid. Examples of sugar acids that can be used in the context of the present invention include but are not limited to glyceric acid, xylonic acid, gluconic acid, ascorbic acid, neuraminic acid, glucuronic acid, galacturonic acid, iduronic acid, tartaric acid, mucic acid and sugar acid. Sugar acid can exist in the form of free acid or salt. According to an embodiment, the salt of sugar acid can be a salt with a metal of group Ia, IIa, Ib, IIb, IVb, VIIIb of the periodic table of elements. In the context of the present invention, it is preferred that sugar acid is not an amide or an ester of sugar acid.

[0115] In the context of the present invention, sugars belong to monosaccharides or disaccharides. Examples of sugars include, but are not limited to, glyceraldehyde, threose, erythrose, xylose, lyxose, ribose, arabinose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, fructose, sorbose, lactose, maltose, sucrose, lactulose, trehalose, cellobiose, chitobiose, isomaltose, palatinose, mannobiose, raffinose, and xylobiose. In the context of the present invention, sugars also relate to molasses, vinasse, and caramel.

[0116] In the context of the present invention, sugar alcohol is a polyol that can be derived from sugar by redox reaction. Therefore, sugar alcohol belongs to alditols. Examples of sugar alcohol include but are not limited to ethylene glycol, glycerol, diglycerol, threitol, erythritol, pentaerythritol, dipentaerythritol, xylitol, ribitol, arabitol, sorbitol, sorbitan, isosorbide, mannitol, galactitol, fucitol, iditol, inositol, heptyl alcohol, lactitol, maltitol, isomalt, maltotriitol, maltotetraol and polyglucanol.

[0117] In the context of the present invention, a hydroxycarboxylic acid is a carboxylic acid that further comprises an OH-moiety within the same molecule. Examples of hydroxycarboxylic acids include, but are not limited to, malic acid, citric acid, isocitric acid, tartronic acid, mandelic acid, salicylic acid, and lactic acid. The hydroxycarboxylic acid may exist in the form of a free acid or as a salt. According to an embodiment, the salt of the hydroxycarboxylic acid may be a salt with ammonium or with a metal of Groups Ia, IIa, Ib, IIb, IVb, VIIIb of the Periodic Table of the Elements. Preferred salts of the hydroxycarboxylic acid are alkali metal salts, alkaline earth metal salts, or ammonium salts.

[0118] According to a preferred embodiment, the additive is selected from sucrose, molasses, galactitol, or an alkali metal salt of gluconic acid, xylonic acid or glucuronic acid.

[0119] According to a particularly preferred embodiment, the additive is sodium gluconate.

[0120] It has been found that amines cannot be used as additives in the process and / or admixtures according to the invention. Amines do not lead to a significant increase in processability. In this context, the term amine also includes N-alkoxylated amines, such as alkanolamines, alkoxylated polyalkylenepolyamines and polyhydroxylated alkyleneamines. Therefore, it is particularly impossible to use alkanolamines and / or polyhydroxylated alkyleneamines as additives according to the invention. Examples of alkanolamines are triethanolamine, triisopropanolamine, diethanolisopropanolamine, methyldiethanolamine, ethanoldiisopropanolamine and tetraethanolethyleneamine. An example of a polyhydroxylated alkyleneamine is tetrakis(hydroxyethyl)ethylenediamine.

[0121] The admixture of the present invention is preferably substantially free of any one or more of alkali metal chlorides and alkaline earth metal chlorides, ammonium chloride, polycationic compounds, and phosphonated polymers. The admixture of the present invention is particularly preferably substantially free of any calcium chloride, sodium chloride, potassium chloride, lithium chloride, ammonium chloride, polyquaternary ammonium acid or salt, such as polydiallyldimethylammonium, epihalohydrin alkylamine condensates, and polyalkoxylated phosphonate polymers. In this context, "substantially free" means that the content of any such material in the admixture of the present invention is less than 1% by weight, preferably less than 0.1% by weight, in each case relative to the total weight of the admixture.

[0122] It has been found that in the method of the present invention the dosage of admixture depends on the composition of the binder composition. Without wishing to be bound by theory, it is believed that the higher the amount of calcined clay in the binder composition, the higher the amount of admixture required.

[0123] According to a preferred embodiment, in the method of the present invention, the admixture of the present invention is added to the binder composition in an amount such that the weight ratio of at least one additive to calcined clay is from 1:1500 to 1:10, preferably from 1:800 to 1:100, more preferably from 1:650 to 1:200, and even more preferably from 1:580 to 1:300. To calculate this weight ratio, the total amount of the additives is taken into account. This means that when one additive is used in the admixture of the present invention, the weight of that one additive is used in the calculation, while when two or more additives are used, the total weight of all additives is used in the calculation.

[0124] According to an embodiment, the weight ratio of the at least one PCE to the calcined clay in the curable composition is between 1:600 and 1:50, preferably between 1:500 and 1:100, and in particular between 1:150 and 1:100. To calculate this weight ratio, the total amount of PCE is taken into account. This means that when one PCE copolymer is used in the admixture of the present invention, the weight of this one PCE copolymer is used in the calculation, and when two or more PCE copolymers are used, the combined weight of all PCE copolymers is used in the calculation.

[0125] According to a particularly preferred embodiment, in the process of the present invention, the at least one PCE and the at least one additive are added in a weight ratio of at least one PCE to at least one additive of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, and in particular 5:1 to 1.5:1.

[0126] In a second aspect, the present invention relates to an admixture that can be used in the above method, the admixture comprising:

[0127] a) at least one PCE,

[0128] b) at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids.

[0129] According to a particularly preferred embodiment of the present invention, at least one additive used in the admixture of the present invention is selected from sucrose, molasses, galactitol, or alkali metal salts of gluconic acid, xylonic acid or glucuronic acid, and a particularly preferred additive is sodium gluconate.

[0130] Preferably, the admixture comprises the at least one PCE and the at least one additive in a weight ratio of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, especially 5:1 to 1.5:1.

[0131] According to an embodiment, the admixture of the present invention further comprises water.

[0132] According to an embodiment, the admixture of the present invention consists of at least one PCE and at least one additive and optionally water, wherein the at least one PCE and the at least one additive have a weight ratio of at least one PCE to at least one additive of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, and especially 5:1 to 1.5:1.

[0133] According to an embodiment, the admixture of the present invention comprises a PCE and an additive, wherein the weight ratio of PCE to additive is 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, especially 5:1 to 1.5:1.

[0134] According to an embodiment, the admixture of the present invention consists of one PCE, at least one additive and optionally water, wherein the PCE and the at least one additive have a weight ratio of PCE to additive of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, and especially 5:1 to 1.5:1.

[0135] According to an embodiment, the admixture of the present invention consists of a PCE, an additive and optionally water, wherein the PCE and the additive have a weight ratio of PCE to additive of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, especially 5:1 to 1.5:1.

[0136] To calculate these weight ratios, the total amount of PCE and the total amount of additives are taken into account. This means that when one PCE is used in the admixture according to the invention, the weight of this one PCE is used for the calculation, and when two or more PCEs are used, the sum of the weights of all PCEs is used for the calculation. The same applies to the additives.

[0137] According to a particularly preferred embodiment, the admixture of the present invention consists of the following components

[0138] a) A PCE

[0139] b) an additive selected from sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids, and

[0140] c) optionally water,

[0141] The PCE and the additive have a weight ratio of PCE to additive of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, especially 5:1 to 1.5:1.

[0142] According to a particularly preferred embodiment of the present invention, the additive used in the admixture of the present invention is selected from sucrose, molasses, galactitol, or alkali metal salts of gluconic acid, xylonic acid or glucuronic acid, and a particularly preferred additive is sodium gluconate.

[0143] According to an embodiment, the admixture of the present invention is a one-component admixture. This means that at least one PCE and at least one additive and optionally other ingredients are premixed in the weight ratios described above. In the case where at least one PCE and the at least one additive are liquids, the one-component admixture can be obtained by mixing two or more liquids by any method known to those skilled in the art. The one-component admixture thus obtained can be a solution, an emulsion or a multiphase mixture. It can be in the form of a liquid or a paste. It can also be further processed to obtain a solid, for example by spray drying. In the case where the at least one PCE and / or the at least one additive are solids, the one-component admixture can be obtained by mixing two or more solids by any method known to those skilled in the art. The one-component admixture thus obtained can be in the form of a powder or a paste. In the case where at least one of the at least one PCE and the at least one additive is a liquid and at least one of the at least one PCE and the at least one additive is a solid, the one-component admixture can be obtained by mixing the compounds by any method known to those skilled in the art or by absorbing at least one liquid onto at least one solid. The one-component thus obtained can be in the form of a solid, a paste, a dispersion or a solution. The other constituents of the admixture, in particular water, can be added alone and / or together with the at least one PCE and / or the at least one additive. According to a particularly preferred embodiment, the at least one PCE is added in the form of a solution or dispersion in water.

[0144] In the method of the present invention, the one-component admixture as described above can be added during the production of the dry binder composition as described above, either together with the mixing water or shortly after the mixing water.

[0145] According to an embodiment, the admixture of the present invention is a two-component admixture. This two-component admixture has two separate components α and β, wherein component α contains at least one PCE as described above, and component β contains at least one additive as described above. Components α and β are stored in separate containers or in spatially separate compartments of a container. Components α and β can be premixed shortly before adding to the binder composition. Premixing can be performed by any method known to those skilled in the art. The premixed components α and β can be added to the dry binder composition together with the mixing water or shortly thereafter. Components α and β can also be metered separately into the binder composition of the present invention. For example, it is possible, and in some cases preferred, to mix both components α and β into the dry binder composition. According to certain embodiments, components α and β are added during the production of the dry binder composition. It is also possible, and in some cases preferred, to mix only one component α or β into the dry binder composition, for example, during or after the production of the dry binder composition, and to add the other component α or β at a subsequent stage, for example, together with or shortly thereafter. Furthermore, one component α or β can be added together with the mixing water or shortly thereafter, while the other component α or β is added at a later stage, for example shortly before or during the setting period. Finally, component α or β can be added together with the mixing water or shortly thereafter.

[0146] In another aspect, the present invention relates to a curable composition obtainable by the process described above.

[0147] The curable composition is characterized in that it comprises:

[0148] a) a binder composition comprising calcined clay (CC), limestone (L) and Portland cement (P), wherein the weight ratio of P:CC is from 33:1 to 1:1, preferably from 8:1 to 1:1, the weight ratio of CC:L is from 10:1 to 1:50, preferably from 10:1 to 1:33, more preferably from 5:1 to 1:10, and the weight ratio of P:L is from 20:1 to 1:4, preferably from 5:1 to 1:1,

[0149] b) at least one PCE, and

[0150] c) at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids.

[0151] According to a particularly preferred embodiment of the present invention, the additive contained in the curable composition of the present invention is selected from sucrose, molasses, galactitol, or alkali metal salts of gluconic acid, xylonic acid or glucuronic acid, and a particularly preferred additive is sodium gluconate.

[0152] According to a preferred embodiment, the at least one PCE and the at least one additive have a weight ratio of at least one PCE to at least one admixture of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, especially 5:1 to 1.5:1.

[0153] According to a preferred embodiment, in the curable composition, the weight ratio of the at least one additive to the calcined clay is from 1:1500 to 1:10, preferably from 1:800 to 1:100, more preferably from 1:650 to 1:200, more preferably from 1:580 to 1:300.

[0154] According to a preferred embodiment, in the curable composition, the weight ratio of at least one PCE to calcined clay is from 1:600 to 1:50, preferably from 1:500 to 1:100, in particular from 1:150 to 1:100.

[0155] According to a preferred embodiment, the curable composition comprises:

[0156] a) a binder composition consisting of:

[0157] -25-100 parts by mass of Portland cement (P)

[0158] - 3-50 parts by mass of calcined clay (CC), in particular metakaolin,

[0159] -5-100 parts by mass of limestone (L),

[0160] b) optionally, 1-8 wt. % calcium sulfate relative to the total dry weight of the binder composition,

[0161] c) at least one PCE, and

[0162] d) at least one additive selected from sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids,

[0163] wherein the weight ratio of the at least one additive to the calcined clay is in the range of 1:1500 to 1:10, preferably 1:800 to 1:100, more preferably 1:650 to 1:200, more preferably 1:580 to 1:300, and

[0164] The weight ratio of the at least one PCE to the calcined clay is in the range of 1:600 to 1:50, preferably 1:500 to 1:100, especially 1:150 to 1:100.

[0165] Preferably, in such a curable composition, the weight ratio of the at least one PCE to the at least one additive is from 20:1 to 1:10, preferably from 10:1 to 1:6, more preferably from 5:1 to 1:2, especially from 5:1 to 1.5:1.

[0166] According to a particularly preferred embodiment of the present invention, the additive contained in the curable composition of the present invention is selected from sucrose, molasses, galactitol, or alkali metal salts of gluconic acid, xylonic acid or glucuronic acid, and a particularly preferred additive is sodium gluconate.

[0167] According to a preferred embodiment, the curable composition consists of:

[0168] a) a binder composition consisting of:

[0169] -25-100 parts by mass of Portland cement (P)

[0170] - 3-50 parts by mass of calcined clay (CC), especially metakaolin,

[0171] -5-100 parts by mass of limestone (L),

[0172] b) optionally, 1-8 wt. % calcium sulfate relative to the total dry weight of the binder composition,

[0173] c) PCE, the weight ratio of PCE to calcined clay being in the range of 1:600 to 1:50, preferably 1:500 to 1:100, in particular 1:150 to 1:100,

[0174] d) sodium gluconate, the weight ratio of sodium gluconate to calcined clay being in the range of 1:1500 to 1:10, preferably 1:800 to 1:100, more preferably 1:650 to 1:200, more preferably 1:580 to 1:300, and

[0175] e) optional water.

[0176] Preferably, in this curable composition, the weight ratio of the at least one PCE to sodium gluconate is from 20:1 to 1:10, preferably from 10:1 to 1:6, more preferably from 5:1 to 1:2, especially from 5:1 to 1.5:1.

[0177] A curable composition as described above and substantially free of water is also referred to in this context as a dry curable composition. Substantially free of water means that the water content is less than 5 wt. %, preferably less than 1 wt. %, in particular less than 0.5 wt. %, relative to the total weight of the curable composition.

[0178] In another aspect, the present invention also relates to the curable composition as described above, characterized in that it further comprises water, and the weight ratio of water to the binder composition is 0.1-0.6, preferably 0.2-0.5, especially 0.2-0.35.

[0179] The water may be any available water, such as distilled water, purified water, tap water, mineral water, spring water, brine, and well water. The use of wastewater is only possible if its composition is known and if any impurities it contains do not contribute to the functionality of any of the other components of the composition of the invention. The use of brine is only possible if its high chloride content and the associated risk of reinforcement corrosion are not significant, for example because there is no embedded reinforcement.

[0180] In the context of this application, such curable compositions mixed with water are also referred to as wet curable compositions. Typically, such curable compositions are mixed with water only shortly before their application. This is because upon contact with water, such curable compositions will begin to harden.

[0181] The method and apparatus for mixing the curable composition as described above with water are not particularly limited and are known to those skilled in the art. Mixing can be continuous, semi-continuous or intermittent. Continuous mixing provides the advantage of high material throughput.

[0182] According to an embodiment, the dry curable composition as described above is in particular a part of a dry mortar, a ready-mixed mortar or a dry concrete. The dry mortar, the ready-mixed mortar or the dry concrete herein may be in the form of a one-component material or in the form of a multi-component material, for example a two-component or three-component material.

[0183] The curable composition of the present invention may also include aggregate. Aggregate can be any material that does not react in the hydration reaction of the hydraulic binder. Aggregate can be any aggregate commonly used in mortar or concrete. Typical aggregates are, for example, rock, crushed stone, gravel, slag, sand, especially quartz sand, river sand and / or machine-made sand, recycled concrete, glass, expanded glass, hollow glass beads, glass ceramics, volcanic rock, pumice, perlite, vermiculite, rubber particles, cork, wood flour, quarry waste, raw, fired or fused soil or clay, porcelain, electrically fused or sintered abrasives, fired carriers, silica xerogels and / or fine aggregate or fillers such as ground limestone, ground dolomite and / or ground aluminum oxide. Aggregates that can be used in the present invention can have any shape and size commonly encountered for such aggregates. Particularly preferred aggregate is sand. Sand is a naturally occurring granular material composed of finely crushed rock or mineral particles. It can be obtained in various shapes and sizes. Examples of suitable sands are quartz sand, limestone sand, river sand or crushed aggregate. Suitable sands are described, for example, in standards ASTM C778 or EN 196-1.

[0184] The curable composition as described above may advantageously further comprise other materials commonly found in the mortar and / or concrete industry, such as fillers, plasticizers and / or superplasticizers, air entraining agents, defoamers, stabilizers, rheology modifiers, in particular thickeners, water reducers, redispersible polymer powders, accelerators, retarders, water repellents, strength enhancing additives, fibers, dust removers, foaming agents, pigments, corrosion inhibitors, biocides, chromium (VI) reducing agents. It may be advantageous to combine two or more of these other materials in one curable composition.

[0185] It should be noted that plasticizers and / or superplasticizers are chemically different from the PCEs described above.

[0186] Therefore, the present invention also relates to a curable composition as described above, which further comprises aggregate and optionally one or more other materials selected from fillers, plasticizers and / or superplasticizers, air entraining agents, defoamers, stabilizers, rheology modifiers, in particular thickeners, water reducers, redispersible polymer powders, accelerators, retarders, waterproofing agents, strength-enhancing additives, fibers, dust removers, foaming agents, pigments, corrosion inhibitors, biocides, chromium (VI) reducing agents. This curable composition can be a dry curable composition or a wet curable composition. It is in particular a mortar or concrete, in particular concrete.

[0187] Therefore, in another aspect, the present invention relates to a curable composition, preferably mortar or concrete, comprising

[0188] a) a binder composition comprising calcined clay (CC), limestone (L) and Portland cement (P), wherein the weight ratio of P:CC is from 33:1 to 1:1, preferably from 8:1 to 1:1, the weight ratio of CC:L is from 10:1 to 1:50, preferably from 10:1 to 1:33, more preferably from 5:1 to 1:10, and the weight ratio of P:L is from 20:1 to 1:4, preferably from 5:1 to 1:1,

[0189] b) at least one PCE, and

[0190] c) at least one additive selected from sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids,

[0191] d) aggregates,

[0192] e) optionally one or more further materials selected from fillers, plasticizers and / or superplasticizers, air entraining agents, defoamers, stabilizers, rheology modifiers, in particular thickeners, water reducers, redispersible polymer powders, accelerators, retarders, water repellents, strength enhancing additives, fibers, dust removers, foaming agents, pigments, corrosion inhibitors, biocides, chromium (VI) reducing agents and

[0193] f) optionally water.

[0194] Preferably, in this curable composition, the at least one PCE and the at least one additive have a weight ratio of at least one PCE to at least one additive of 20:1 to 1:10, preferably 10:1 to 1:6, more preferably 5:1 to 1:2, especially 5:1 to 1.5:1.

[0195] According to a preferred embodiment, in such a curable composition, the weight ratio of the at least one additive to the calcined clay is in the range of 1:1500 to 1:10, preferably 1:800 to 1:100, more preferably 1:650 to 1:200, more preferably 1:580 to 1:300.

[0196] According to a preferred embodiment, the weight ratio of PCE to calcined clay in such a curable composition, preferably in a mortar or concrete, is in the range of 1:600 to 1:50, preferably 1:500 to 1:100, in particular 1:150 to 1:100.

[0197] According to an embodiment, water is present in a weight ratio of water to binder composition of 0.1-0.6, preferably 0.2-0.5, especially 0.2-0.35.

[0198] After mixing with water, the curable composition of the present invention will begin to solidify and harden. The solidification and hardening of the wet curable composition of the present invention proceeds over time, thereby developing physical properties, such as compressive strength. The wet curable composition of the present invention will harden at various temperatures. According to an embodiment, the wet curable composition of the present invention hardens at a temperature between +4°C and +50°C, preferably between +5°C and +35°C. According to another embodiment, the wet curable composition of the present invention hardens at a temperature above 50°C and up to 150°C. Such high temperatures can be encountered, for example, in tunneling or mining applications, such as in oil wells. It is highly preferred to harden the wet curable composition of the present invention at a pressure of about 1023 mbar. The wet curable composition of the present invention can also be hardened and cured under elevated pressure, such as in an autoclave. Hardening and curing are typically completed after 28 days. However, depending in particular on the temperature, pressure and humidity, hardening and curing may have been completed after less than 28 days or may last longer than 28 days.

[0199] In another aspect, the present invention relates to a hardened body obtained by hardening and curing the moisture-curable composition of the present invention, in particular a mortar or concrete.

[0200] The following examples will provide other embodiments of the present invention to those skilled in the art. They are not intended to limit the present invention in any way. Example

[0201] The slump flow at different times was measured according to the slump flow test of EN 12350-8 for Examples 1-4 and according to EN 12350-5 for Example 5. The slump flow is therefore a measure of the workability of the respective mix. The slump flow test was performed on each sample at a specified time point after mixing with the mixing water. The respective times are given in Tables 2-12 below. The cone diameter used for the slump flow measurement was 37.5 mm, so the value of 37.5 mm in Tables 2-13 below (Examples 1-4) corresponds to a mix with essentially no slump flow. In Tables 14 and 15 (Examples 5 and 6), the term "not measurable" is used for cases where the slump flow could not be essentially measured.

[0202] Heat flow curves are measured according to the isothermal method described in standard ASTM C1702-17. The examples were measured using an I-CAL 8000 from Calmetrix or a TAM AIR from TM Instruments. The maximum heat release (maximum heat release) reported in the table below is the time after each heat flow curve reaches its overall maximum. The time required to reach this overall maximum is a measure of the hardening rate and, for example, a measure of strength development. Shorter times are associated with faster hardening.

[0203] The compressive strength was measured in accordance with DIN EN 196-1 on prisms measuring 40×40×160 mm after the times indicated in the table below.

[0204] Sodium gluconate, mannitol, galactitol, sucrose, glucose, maltose, lactose, sorbitol, ascorbic acid, sodium glucuronate, lithium xylonate, citric acid, sodium citrate, triethanolamine, and triisopropanolamine were purchased from Sigma-Aldrich with a purity of ≥95%.

[0205] An overview of the other chemicals used is given below in Table 1. Unless otherwise stated, all chemicals were used as supplied.

[0206] Table 1: Chemicals used

[0207]

[0208]

[0209] Reference Examples

[0210] Reference Examples Ref-1 to Ref-4 were prepared by adding the respective amounts of PCE, sodium gluconate, and water shown in Table 2 below to the respective amounts of OPC. The resulting mixtures were mixed for 2 minutes at 1500 rpm on a Heidolph spiral mixer. After these 2-minute mixing times, the respective tests were started.

[0211] Table 2: Compositions of Reference Examples Ref-1 to Ref-4 (all figures are in grams by weight unless otherwise stated).

[0212] Ref-1 Ref-2 Ref-3 Ref-4 OPC 100 100 100 100 PCE-1 0 0.053 0 0.053 Sodium gluconate 0 0 0.025 0.025 water 46 46 46 46 Slump@0min[mm] 93 95 103 124 Slump@30min[mm] 93 90 86 95 Slump@60min[mm] 94 89 85 98 Slump@90min[mm] 75 84 85 95 Slump@120min[mm] 37.5 85 84 92 Maximum heat release [h] 9.74 12.29 12.77 16.11

[0213] The reference examples in Table 2 show that the addition of PCE or sodium gluconate can have a positive effect on the initial slump expansion and slump life of a mixture based on pure Portland cement, and thus on its workability (compare Ref-2 and Ref-3 with Ref-1). As can be seen from the time to reach the maximum exotherm of the system, mixing can be delayed by either addition. The synergistic improvement in slump life observed by the co-addition of PCE and sodium gluconate (Ref-4) is only small in this case and insufficient for practical application. The delay in the system after the addition of PCE and sodium gluconate increases, but is still acceptable for practical application.

[0214] Example 1

[0215] The corresponding binders for the preparation of references Ref-1 to Ref-5 (which are not according to the invention) and examples 1-1 to 1-20 (which are according to the invention) were prepared by mixing OPC, metakaolin, limestone and gypsum in the amounts shown in Table 3 below on a Heidolph propeller mixer at 1500 rpm for 2 minutes in a dry state at 23° C. / 50% relative humidity. In each case, a visually homogeneous powder was obtained.

[0216] Table 3: Composition of binders 1-14 (all numbers are in parts by mass)

[0217]

[0218]

[0219] The corresponding amounts of PCE, sodium gluconate, and water shown in Tables 4-6 below were then added to the binder compositions of the types and amounts shown in these tables. The resulting mixtures were mixed on a Heidolph spiral mixer at 1500 rpm for 2 minutes. After these 2-minute mixing times, the respective tests were started.

[0220] Tables 4 to 6 below show that when the admixture of the present invention is used, the initial slump expansion and slump life, and thus the workability, of each binder composition are significantly improved compared to the initial slump expansion and slump life, and thus the workability, of the same binder composition using only PCE or only the additive (compare Examples 1-1 to 1-4 with Ref-5 to Ref-7, compare Examples 1-5 to 1-8 with Ref-8 to Ref-10, compare Examples 1-9 to 1-12 with Ref-11 to Ref-13, compare Examples 1-13 to 1-16 with Ref-14 to Ref-16, and compare Examples 1-17 to 1-20 with Ref-17 to Ref-19).

[0221] Tables 4-6 also show that the use of the admixtures of the present invention increases the time required to reach the maximum exotherm to some extent. However, all of Inventive Examples 1-1 to 1-20 exhibit acceptable times to the maximum exotherm and, therefore, acceptable compressive strength development. A maximum time to the maximum exotherm of 20 hours is acceptable for the present invention.

[0222] The admixture of the present invention is therefore able to increase the initial slump expansion and slump life of a binder composition comprising Portland cement, calcined clay and limestone, thereby improving workability, while maintaining a strength development that is fully acceptable for practical applications.

[0223]

[0224]

[0225]

[0226] Example 2

[0227] Example 2 shows the effect of different additives.

[0228] Inventive Examples 2-1 to 2-44 were prepared in the same manner as the above Examples 1-1 to 1-20, except that different additives were used (see Tables 7-10 for details).

[0229] Tables 7-10 below show that the additives of the present invention can improve the initial slump expansion, especially the slump life, of the binder composition of the present invention, and thus improve the workability. All Examples 2-1 to 2-44 can be compared with Ref-5 to Ref-7 of Example 1.

[0230]

[0231]

[0232]

[0233]

[0234]

[0235] The above-mentioned reference examples Ref-20 to Ref-25 show that the use of triethanolamine (TEA) or triisopropanolamine (TIPA) does not improve the processability of the binder composition of the present invention to a satisfactory degree (for example, compared with reference example Ref-5 and examples 1-1 to 1-4).

[0236] Example 3

[0237] Example 3 shows the effect of different PCEs.

[0238] Inventive Examples 3-1 to 3-10 and Reference Examples Ref-26 to Ref-28 (which are not according to the present invention) were prepared in the same manner as the above Examples 1-1 to 1-20, except that different PCEs were used. Example 3-1 is the same as Example 1-4.

[0239] Table 12 below shows that PCEs of different structures, when combined with the additives of the present invention, can improve the initial slump expansion, especially the slump life, of the binder composition of the present invention, thereby improving workability. Without the addition of additives, PCEs do not work in the same manner (see Reference Examples Ref-26 to Ref-28).

[0240]

[0241] Example 4

[0242] Example 4 shows the effect of different doses of PCE at a fixed dose of sodium gluconate.

[0243] Inventive Examples 4-1 to 4-20 were prepared in the same manner as the above-mentioned Examples 1-1 to 1-20, except that the dosages of PCE and sodium gluconate shown in Table 13 below were used.

[0244] Table 13 below shows that when the admixture according to the invention is used, the initial slump flow as well as the slump life and therefore the workability of the respective binder compositions can be significantly improved, if compared with reference compositions without PCE and / or without additives (reference examples Ref-5 to Ref-19 compared with Example 1).

[0245] Similar to the results of Example 1, the results in Table 13 show that the use of the admixture of the present invention increases the time required to reach maximum exotherm to some extent. However, all of Inventive Examples 4-1 to 4-20 show acceptable times to maximum exotherm and, therefore, acceptable development of compressive strength.

[0246] The admixture of the present invention is therefore able to increase the initial slump expansion and slump life of a binder composition comprising Portland cement, calcined clay and limestone, thereby improving workability, while maintaining a strength development that is fully acceptable for practical applications.

[0247]

[0248]

[0249]

[0250] Example 5

[0251] Example 5 shows the effect of adding the admixture of the present invention to a mortar composition based on a binder comprising ordinary Portland cement, metakaolin, limestone and gypsum.

[0252] Inventive Examples 5-1 to 5-10 and Reference Examples Ref-29 to Ref-36 (which are not in accordance with the present invention) were prepared by mixing binder, PCE, sodium gluconate, limestone, and aggregate in the amounts given in Table 14 below on a Heidolph propeller mixer at 1500 rpm for 1 minute at 23°C / 50% relative humidity. A visually homogeneous powder was obtained in each case. Water was added in an amount to achieve a water to binder ratio (w / b) of 0.5 in each case. Mixing was then continued on the Heidolph propeller mixer at 1500 rpm for 3 minutes.

[0253] The measurements were performed as described above.

[0254]

[0255] Table 14 (continued)

[0256] Ref-34 5-6 5-7 5-8 Ref-35 5-9 5-10 Ref-36 Binder 6 100 100 100 100 100 100 100 100 PCE-1 0.18 0.18 0.18 0.18 0.24 0.24 0.24 0.3 Sodium gluconate 0.04 0.075 0.15 0.025 0.05 limestone 18.8 18.8 18.8 18.8 18.8 18.8 18.8 18.8 Aggregate 400 400 400 400 400 400 400 400 water 50 50 50 50 50 50 50 50 Slump@0min[mm] 216 258 254 258 255 260 268 216 Slump@30min[mm] 195 253 248 242 233 255 260 268 Slump@60min[mm] 163 232 236 240 197 230 251 256 Slump@90min[mm] 142 213 224 235 166 205 238 248 Slump@120min[mm] nm 228 151 154 240 Compressive strength@1d[MPa] 10 9.5 7.8 8 8.8 Compressive strength@2d[MPa] 18.8 19.1 17.8 17.1 18.4

[0257] nm: unmeasurable

[0258] As can be seen from Table 14 above, the addition of the admixture of the present invention to the binder of the present invention results in better workability, especially higher slump flow, compared to the same composition containing only PCE. At the same time, the compressive strengths of the examples of the present invention measured after 1 day and 2 days are at the same level as the compressive strengths of the reference examples. Therefore, the delay in curing is acceptable for practical applications. It can also be seen from the results of Table 14 that the effect of the admixture of the present invention on the binder composition of the present invention is similar to the increase in PCE dosage. The method of the present invention is also a way to reduce the PCE dosage in the binder composition of the present invention.

[0259] Example 6

[0260] Example 6 shows the effect of the admixture of the present invention on a binder comprising calcined clay, limestone and Portland cement in varying proportions.

[0261] Examples 6-1 to 6-14 and Reference Examples Ref-37 to Ref-43 were prepared and measured in the same manner as Examples 1-1 to 1-20 above. Table 15 below shows the type of binder used, the dosage of the admixture, and the slump flow values measured after different times, as well as the maximum exotherm time. The dosage of each admixture used was set to obtain an initial slump of approximately 140 mm. Examples 6-1 to 6-14 are in accordance with the present invention, while Examples Ref37 to Ref43 are comparative examples and are not in accordance with the present invention.

[0262] Table 15: Compositions of Examples 6-1 to 6-14 and Ref37 to Ref43 (all figures are in grams unless otherwise stated)

[0263] Ref37 6-1 6-2 Ref38 6-3 6-4 Ref39 6-5 6-6 Binder 7 100 100 100 Binder 8 100 100 100 Binder 9 100 100 100 PCE-1 0.033 0.026 0.029 0.141 0.1 0.131 0.132 0.093 0.109 Sodium gluconate 0.013 0.007 0.046 0.031 0.045 0.026 water 46 46 46 46 46 46 46 46 46 Slump@0min[mm] 139 137 140 143 142 143 143 140 140 Slump@30min[mm] 132 131 125 136 151 150 152 143 143 Slump@60min[mm] 126 123 124 126 153 148 164 140 140 Slump@90min[mm] 130 117 124 95 156 149 152 141 141 Slump@120min[mm] 129 120 122 nm 154 146 148 141 141 Maximum heat release [h] 13.11 17.24 14.76 12.16 34.36 16.68 18.89 33.3 23.56

[0264]

[0265] As can be seen from Table 15 above, when the admixture of the present invention is used, an improvement in slump life can be achieved only in some cases compared to using PCE alone (6-3 and 6-4 compared to Ref 38, 6-12 compared to Ref 42). It should be noted that in the case of Examples 6-3, 6-4, and 6-12, additional fluidization (increase in slump spread) over time is observed, which is undesirable.

Claims

1. A method for increasing the workability of a binder composition comprising calcined clay, limestone and Portland cement, said method comprising the step of adding an admixture comprising at least one polycarboxylate ether (PCE) and at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids; It is characterized by The binder composition comprises calcined clay CC, limestone L and Portland cement P in the following weight ratios: P:CC is 8:1 to 1:1, CC:L is 10:1 to 1:10, and P:L is 5:1 to 1:1; wherein the at least one PCE and the at least one additive are added in a weight ratio of the at least one PCE to the at least one additive of 20:1 to 1:2, and The admixture does not contain a phosphonated polymer.

2. The method according to claim 1, characterized in that The at least one polycarboxylate ether PCE is a copolymer or a mixture of two or more copolymers, wherein each copolymer comprises (i) a repeating unit A of the general structure (I), and (ii) a repeating unit B of the general structure (II), in Each R u are independently H or methyl, Each R v independently of each other, H or COOM, Each M is independently H, an alkali metal ion or an alkaline earth metal ion, m=0, 1, 2 or 3, p = 0 or 1, Each R 1 Independently of each other -[YO] n -R 4 , wherein Y is C2-C4 alkylene, R 4 is H, C1-C20 alkyl, cyclohexyl or C1-C20-alkylaryl, and n=2-350, And the molar ratio of repeating units A and B in the copolymer is A:B in the range of 10:90-90:

10.

3. The method according to claim 2, characterized in that The molar ratio of repeating units A and B in the copolymer is 20:80-80:

20.

4. The method according to claim 2, characterized in that The molar ratio of repeating units A and B in the copolymer is 30:70-80:

20.

5. The method according to claim 2, characterized in that The molar ratio of repeating units A and B in the copolymer is 35:65-75:

25.

6. The method according to claim 1, characterized in that CC:L is 5:1 to 1:

10.

7. The method according to any one of the preceding claims 1 to 5, characterized in that The calcined clay is metakaolin.

8. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that the weight ratio of the at least one additive to the calcined clay is 1:1500 to 1:

10.

9. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that a weight ratio of the at least one additive to the calcined clay is 1:800 to 1:

100.

10. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that the weight ratio of the at least one additive to the calcined clay is 1:650 to 1:

200.

11. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that the weight ratio of the at least one additive to the calcined clay is 1:580 to 1:

300.

12. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that the weight ratio of the at least one PCE to the calcined clay is from 1:600 to 1:

50.

13. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that the weight ratio of the at least one PCE to the calcined clay is from 1:500 to 1:

100.

14. The method according to any one of the preceding claims 1 to 5, characterized in that The admixture is added to the binder composition in an amount such that the weight ratio of the at least one PCE to the calcined clay is from 1:150 to 1:

100.

15. The method according to any one of the preceding claims 1 to 5, characterized in that The at least one PCE and the at least one additive are added in a weight ratio of the at least one PCE to the at least one additive of 10:1 to 1:

2.

16. The method according to any one of the preceding claims 1 to 5, characterized in that The at least one PCE and the at least one additive are added in a weight ratio of the at least one PCE to the at least one additive of 5:1 to 1:

2.

17. The method according to any one of the preceding claims 1 to 5, characterized in that The at least one PCE and the at least one additive are added in a weight ratio of the at least one PCE to the at least one additive of 5:1 to 1.5:

1.

18. An admixture for use in the method according to any one of the preceding claims 1 to 17, comprising: a) at least one PCE, b) at least one additive selected from sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids; and It is characterized by: The admixture does not contain a phosphonated polymer.

19. An admixture according to claim 18, characterized in that It is a single component admixture.

20. An admixture according to claim 19, characterized in that It is a two-component admixture.

21. An admixture according to any one of claims 18 to 20, characterised in that It consists of the following ingredients: a) a PCE, b) an additive selected from sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids, and c) optionally water, The PCE and the additive have a weight ratio of PCE to the additive of 20:1 to 1:

2.

22. An admixture according to claim 21, characterized in that The PCE and the additive have a weight ratio of PCE to the additive of 10:1 to 1:

2.

23. The admixture according to claim 21, characterized in that The PCE and the additive have a weight ratio of PCE to the additive of 5:1 to 1:

2.

24. The admixture according to claim 21, characterized in that The PCE and the additive have a weight ratio of PCE to the additive of 5:1 to 1.5:

1.

25. A curable composition obtainable by the method of any one of claims 1 to 17.

26. The curable composition according to claim 25, characterized in that It includes: a) a binder composition comprising calcined clay CC, limestone L and Portland cement P, wherein P:CC is from 8:1 to 1:1, CC:L is from 10:1 to 1:10, and P:L is from 5:1 to 1:1, b) at least one PCE, and c) at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols and hydroxycarboxylic acids.

27. The curable composition according to claim 26, characterized in that CC:L is 5:1 to 1:

10.

28. The curable composition according to any one of claims 25 to 27, characterized in that The curable composition further comprises water, and the weight ratio of water to the binder composition is 0.1 to 0.

6.

29. The curable composition according to claim 28, characterized in that The weight ratio of water to the binder composition is 0.2 to 0.

5.

30. The curable composition according to claim 28, wherein The weight ratio of water to the binder composition is 0.2 to 0.

35.

31. A hardened body obtained by curing the curable composition according to any one of claims 28 to 30.

32. The hardened body according to claim 31, wherein the curable composition is mortar or concrete.

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